Apparatus for transporting and storing cylinders

ABSTRACT

The invention provides a cylinder skid for transporting and storing cylinders in a stackable configuration within a cargo shipping container. In one embodiment, the cylinder skid includes four vertical members attached to a horizontal base. Extending from the top of each vertical member is a stacking means, for example a pin. In another embodiment, a second cylinder skid has a horizontal base including four receiving means, for example four holes on the bottom of the horizontal base, for receiving each of the stacking means.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from International Application Ser. No. PCT/US2006/032391, filed 18 Aug. 2006, published as WO 2008/020854 A1, with publication date 21 Feb. 2008.

FIELD OF THE INVENTION

The present invention relates to an apparatus for transporting and storing cylinders. More specifically, the present invention provides a novel cylinder skid for transporting and storing cylinders in a stackable configuration within a cargo shipping container.

BACKGROUND OF THE INVENTION

Fluids are often transported in cylinders (e.g., 450 liter DOT 3AA high pressure steel cylinders also known as ton containers or Y-cylinders) between locations all over the world. For example, a manufacturer may fill a ton container in Texas and ship it to a consumer in Australia. The ton containers are typically loaded onto cargo shipping containers which may be transported over land, rail and sea. Accordingly, a variety of forces act on the ton containers and their supporting skids during transport. For example, highway transit creates lateral, vertical and longitudinal shocks and vibration resulting from braking and acceleration, impact with loading docks, and sway in turning and cornering. Such forces typically equal about 1.5 G. Railway transportation produces similar lateral, vertical and longitudinal stresses, but to a greater degree than those experienced in highway transit. This is partly due to the intensity and duration of humping operations in rail depots. Railway forces typically equal 4.0 G. Ocean transit produces an even wider range of motions, resulting from the free flowing nature of water. For example, dynamic motions about a ship's axis include: yawing, rolling, and pitching. In addition, there are bodily motions: heave, sway and surge. In heavy seas, a loaded cargo shipping container may travel over an arc of 70 degrees with each complete roll of the ship, and this can occur 7 to 10 times per minute. In heavy seas, a roll of 40 to 50 degrees is common. Dynamic forces from severe storms cause the most severe stresses as compared to all other modes of transport. Even under normal conditions, forces from 1.8 to 2.4 G can be expected during ocean transport.

For decades, ton containers carrying liquids, liquefied gases and compressed gases have been shipped in cargo shipping containers in a single-level arrangement. In this arrangement, the cylinders lie in a horizontal orientation on the floor and parallel to the long-axis of the cargo container. Shipping the ton containers in a vertical orientation is precluded due to their length relative to the height of the cargo containers.

FIG. 1 illustrates a standard ton container and FIG. 2 shows a typical arrangement for transporting such ton containers in a cargo shipping container. The ton containers have a length of 7 feet 11¼ inches and an outer diameter of 2 feet. A standard cargo container has a width of 8 feet, a height of 8½ feet and one of five common lengths: 20 feet, 40 feet, 45 feet, 48 feet and 53 feet. The ton containers are typically placed in a cylinder skid and secured using ratcheted nylon straps. As mentioned, the cylinders are positioned horizontally and parallel to the long axis of the cargo container due to their length which when combined with the skid exceeds the height and width of the cargo container. As shown in FIG. 2, the cylinders are arranged in a single row with a maximum of three cylinders across the width of the cargo container. The prior art cylinder skid arrangement only permits transportation of six (6) cylinders per 20 foot cargo container or 12 cylinders per 40 foot cargo container and utilizes 21 square feet of cargo space to store a single cylinder.

A standard prior art cylinder skid 300 is shown in FIG. 3. The skid 300 includes two three inch by seven inch (3″×7″) longitudinal beams 301, 303 positioned parallel to each other and connected by two 3″×7″ lateral beams 305, 307 arranged perpendicular to the longitudinal beams 301, 303. The lateral beams 305, 307 are spaced to provide fork truck lift points. The longitudinal beams 301, 303 are welded on top of beams 305, 307 as shown. The skid 300 also includes two 3″×3″ members that are welded to the ends of each longitudinal beam 301, 303 as well as two end stops 313, 315. The end stops 313, 315 have a triangular cross-section and prevent longitudinal movement of a cylinder (not shown) when installed in the skid 300. In addition, two pairs of side stops 317, 319 are also attached to beams 301, 303 to prevent lateral movement of the cylinder during transport. The prior art cylinder skid 300 is constructed of galvanized stainless steel.

While the prior art skid 300 is sufficient for shipping ton containers, the space above the cylinders in the cargo shipping containers is not utilized. Thus, there exists a need for an improved cylinder skid for transporting and storing ton containers in a stacked configuration in cargo shipping containers.

BRIEF DESCRIPTION OF THE INVENTION

It is an object of the present invention to provide a cylinder skid comprising a horizontal base, a plurality of vertical members connected to the horizontal base and a stacking means extending from each vertical member.

It is another object of the present invention to provide a skid for transporting and storing cylinders comprising a first horizontal base, a second horizontal base wherein a bottom surface of the second horizontal base forms a plurality of receiving means, a plurality of vertical members connected to the first horizontal base and a stacking means extending from the top of each vertical member.

Yet another object of the invention is to provide a stackable cylinder skid comprising a first unit defining a space for holding a cylinder comprising a horizontal base having a plurality of longitudinal members and a lateral member connected perpendicularly and joining the plurality of longitudinal members, a plurality of vertical members connected to the lateral member, and a stacking means extending from the top of each vertical member, and a second unit defining a space for holding a cylinder comprising a horizontal base having a plurality of longitudinal members, and a plurality of vertical members connected to the lateral member wherein the second unit includes receiving means located on a bottom surface of the horizontal base of the second unit and adapted to receive the stacking means of the first unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the dimensions of a standard ton container.

FIG. 2 is a schematic representation of ton containers loaded on a cargo shipping container.

FIG. 3 is a schematic diagram of a prior art cylinder skid.

FIG. 4A is a lateral view of an embodiment of the cylinder skid according to the present invention.

FIG. 4B is a plan view of an embodiment of the cylinder skid according to the present invention.

FIG. 4C is a longitudinal view of an embodiment of the cylinder skid according to the present invention.

FIG. 4D is an orthogonal view of an embodiment of the cylinder skid according to the present invention.

FIG. 5 is a schematic diagram of an embodiment of the pin assembly and locking mechanism for the vertical members.

FIG. 6 is a schematic diagram of a stacked arrangement of the cylinder skids according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an apparatus for storing and transporting cylinders (e.g., 450 liter 3AA high pressure steel cylinders also known as ton containers or Y-cylinders) in a stacked configuration. More particularly, the invention is a novel cylinder skid for stacking ton containers during transport and storage. Notably, the stackable configuration of the cylinder skid according to the present invention doubles the number of cylinders that can be shipped and stored in cargo shipping containers (i.e., 12 cylinders per 20 foot cargo container and 24 cylinders per 40 foot cargo container, two cylinders per 21 square feet).

FIG. 4 shows an embodiment of the cylinder skid 400 according to the present invention. The cylinder skid 400 includes two longitudinal members 401, 403 (e.g., two 3″×7″ beams) that are arranged in parallel and connected by two lateral members 405, 407 (e.g., two 3″×7″ beams). The longitudinal members 401, 403 and lateral members 405, 407 together form a horizontal base of the skid. The lateral members 405, 407 are spaced apart not only to provide optimal structural support for the horizontal base, but also to permit insertion of fork lift truck tines (not shown) into the lateral members 405, 407. For safety reasons, the fork lift truck tines need to fit into the lateral members 405, 407 during transport of the cylinder skid 400. A third lateral member 409 may also be connected to the horizontal base to accommodate the tines of a fork lift truck that may not be able to spread the tines wide enough to insert into lateral members 405, 407. The cylinder skid 400 also includes two end stops 411, 413 connected across the longitudinal members 401, 403 to prevent longitudinal movement of the cylinder (not shown) when loaded onto the skid 400. The end stops 411, 413 may be of any geometry sufficient to prevent longitudinal movement of the cylinder, but preferably the end stops 411, 413 have a triangular cross-section as shown in FIG. 4A. In addition, end members 412, 414 (e.g., 3″×3″ metal pieces) are also connected across the longitudinal members 401, 403.

The skid 400 further includes a vertical member connected to the horizontal base, preferably four vertical members 415, 419 and 417, 421 connected to the horizontal base as shown in FIGS. 4A-4D. The vertical members 415, 419 and 417, 421 are preferably completely integrated with or integrally connected to (e.g., bolted and welded to) the lateral members 405 and 407, respectively, thereby adding significant strength and durability to the skid frame. Alternatively, the vertical members 415, 419, and 417, 421 may be connected to the longitudinal members 401 and 403, respectively, or they may be connected to both the longitudinal members and the lateral members.

When connected, the vertical members 415, 417, 419, 421, longitudinal members 401, 403, and lateral members 405, 407 define a cylinder space for holding a ton container as shown by the dash-dot line in FIG. 4C. The vertical members 415, 417, 419, 421, longitudinal members 401, 403, and lateral members 405, 407 are positioned so that when a cylinder is loaded onto the skid, the cylinder valve centerline height is preferably 14 inches above the base of the skid for optimal stability.

Each vertical member 415, 417, 419, 421 includes a stacking means, for example a pin 431, 433, 435, 437, that enables the stacking of one cylinder skid on top of another. Preferably, the pin is of circular cross-section (e.g., about ⅝ inch in diameter and about 2 inches long) and may be a bolt. In addition, the pin 431, 433, 435, 437 could be of any geometrical cross-section such as a square, triangle or pentagon. The horizontal base of each skid 400 preferably includes a receiving means 432, 434 for each pin 431, 433, 435, 437 two of which are shown in FIG. 4D. The receiving means 432, 434 may be a hole drilled into one of the lateral beams 405, 407 and positioned directly beneath one of the vertical beams 415, 417, 419, 421 for optimal strength and structural stability. Preferably, the hole is of the same cross-section as the pin and the outer diameter of the pin is within a close tolerance to the diameter of the hole so that when a first skid is placed on top of a second skid, the pins of the first skid fit snuggly into the holes of the second skid. The stacking means and receiving means together with the weight of the cylinder prevent movement of the cylinder skids in the vertical and longitudinal directions. The vertical members 415, 417, 419, 421 prevent lateral movement of the cylinder and cylinder skids. Notably, the stacking means and receiving means may be any mechanical structure that maintains the skids in a stacked configuration. For example, the pins may be positioned on the bottom of each horizontal base whereas the holes are formed in the top of the vertical members 415, 417, 419, 421. In addition, 2″×4″ holes could also be formed in the bottom of each horizontal base so that the 2″×4″ vertical members 415, 417, 419, 421 become the stacking means in this embodiment and slide into the 2″×4″ holes.

The cylinder skids may also include a locking means, for example, a locking pin 501 as shown in FIG. 5, to maintain the cylinder skids in a stacked configuration during transportation. Preferably, the locking means would have no separate parts that could be lost during transportation of the cylinders. The locking pin might be a screw that threads through the vertical member 503 and the base member (not shown) or it could be a nut and bolt. Any type of locking pin could be used.

Referring again to FIG. 4, the cylinder skid 400 may include padding to prevent both longitudinal and lateral movement of the cylinder during transport. The end stops 411, 413 may include end pads 416, 418 to cushion the cylinder (not shown) in the longitudinal direction. In addition, lateral movement is minimized with side pads 420, 422, 424, 426 connected to the vertical members 415, 417, 419, 421 and lateral members 405, 407 as shown in FIG. 4C. The side pads 420, 422, 424, 426 may be angled to provide a stable seat for the cylinder. During transport, each cylinder is preferably secured to its respective skid with ratcheted straps. Furthermore, a “block and brace” technique is used within the cargo shipping container to prevent vertical movement of the cylinder skids during transportation. Block and brace elements include wooden 2″×4″ beams and 4″×4″ beams nailed to the floors, walls and ceilings of the cargo shipping containers. Blocking and bracing prevents movement of the cylinders in all directions during transport, particularly during ocean transit. Blocking and bracing in the vertical direction may also prevent the top skid from jumping off of the pins of the skid below.

FIG. 6 shows two cylinder skids (identical to the one shown in FIG. 4) in a stacked configuration 600. Skid 603 is positioned above skid 601 thereby defining two spaces, one above each skid 601, 603. Each space is at least large enough to hold one cylinder as shown by the dash-dot lines in FIG. 6. Often a cylinder is enclosed in a leak containment device during transport and storage. Such leak containment devices, however, differ between manufacturers and users, thus, the spaces must be large enough to hold cylinders enclosed in a variety of leak containment devices. In addition, the dimensions of the skids are such that the leak containment devices and cylinder valves are readily accessible. For certain products, manufacturers and consumers may also use heating blankets to maintain steady delivery pressures. Thus, the skids must also permit use of heating blankets. Notably, the cylinder skids of the present invention must be constructed so that the lower skid 601 can support the weight of the upper skid 603 when loaded with a filled ton container (the total weight of a filled ton container and a single skid is approximately 2625 lb_(f)). In addition, the cylinders individually and when stacked and loaded with cylinders must be able to withstand the forces experienced during road, rail and ocean transportation as described above.

In other embodiments of the invention, the cylinder skid may be constructed in a stacked configuration as shown in FIG. 6. For example, the eight vertical elements may be replaced with four solid beams (not shown) that are connected to both horizontal bases. The solid beams may be welded to the sides of the longitudinal and/or lateral elements of each horizontal base or may pass through a 2″×4″ hole formed in each base. Like the embodiment shown in FIG. 6, in this embodiment the horizontal bases must form two spaces large enough to hold two ton containers during shipping.

The cylinder skids of the present invention can be constructed of any rigid and anti-corrosive material sufficient to withstand the various forces applied to the assembly when carrying cylinders over land, rail or sea. Preferably, all of the longitudinal, lateral and vertical members are constructed of a tube steel that is either galvanized or painted to withstand corrosion. All joints are preferably bolted and welded to withstand applied forces and corrosion. The pads may be constructed of plastic, rubber or foam and are preferably resistant to corrosion.

The present invention as described above and shown provides a novel apparatus for storing and transporting compressed gas cylinders in a stackable configuration. It is anticipated that other embodiments and variations of the present invention will become readily apparent to the skilled artisan in light of the foregoing description and examples, and it is intended that such embodiments and variations likewise be included within the scope of the invention as set forth in the following claims. 

1. A cylinder skid comprising: a horizontal base; a plurality of vertical members connected to the horizontal base; and a stacking means extending from each vertical member.
 2. The cylinder skid of claim 1 wherein the horizontal base comprises a plurality of longitudinal members and a lateral member connected perpendicularly to the plurality of longitudinal members.
 3. The cylinder skid of claim 2 wherein the plurality of vertical members are integrated with the lateral member.
 4. The cylinder skid of claim 1 wherein each stacking means comprises a pin.
 5. The cylinder skid of claim 4 wherein the pin has a diameter of about ⅝ inch and a length of about 2 inches.
 6. The cylinder skid of claim 1 wherein each stacking means is adapted to be positioned in a receiving means.
 7. The cylinder skid of claim 6 wherein each stacking means is adapted to be positioned in different receiving means.
 8. The cylinder skid of claim 6 wherein the receiving means is formed in a horizontal base of a second cylinder skid.
 9. The cylinder skid of claim 1 further comprising a cargo shipping container wherein the cylinder skid is positioned in the cargo shipping container.
 10. A skid for transporting and storing cylinders comprising: a first horizontal base; a second horizontal base wherein a plurality of receiving means is formed on a bottom surface of the second horizontal base; a plurality of vertical members connected to the first horizontal base; and a stacking means extending from the top of each vertical member.
 11. The skid according to claim 10 further comprising a cargo shipping container wherein the skid is positioned in the cargo shipping container.
 12. A stackable cylinder skid comprising: a first unit defining a space for holding a cylinder comprising a horizontal base having a plurality of longitudinal members and a lateral member connected perpendicularly and joining the plurality of longitudinal members, a plurality of vertical members connected to the lateral member, and a stacking means extending from the top of each vertical member; and a second unit defining a space for holding a cylinder comprising a horizontal base having a plurality of longitudinal members, and a plurality of vertical members connected to the lateral member; wherein the second unit includes receiving means located on a bottom surface of the horizontal base of the second unit and adapted to receive the stacking means of the first unit. 